The field of invention is X-ray markers, more particularly X-ray markers formed from a single composite material.
X-ray markers are used to identify images produced using X-ray imaging. The markers are disposed between an X-ray source and X-ray sensitive image receptor, such as film, and produce identifying indicia on the image receptor by selectively blocking X-rays emitted by the source.
A typical X-ray marker, such as described in U.S. Pat. Nos. 4,035,653 and 4,121,108, is formed by shaping an X-ray absorbing material, such as lead, in the form of a predetermined identifying indicia. The shaped material is then encapsulated in a plastic which does not absorb X-rays to form the marker.
Other methods of forming an X-ray marker such as disclosed in U.S. Pat. No. 4,274,006 includes concentrating a lead powder in grooves formed in a plastic plate. The patterns define the desired indicia. In U.S. Pat. No. 5,394,456, materials having different X-ray attenuating properties is disclosed which are overlapped to form a pattern having a greater X-ray attenuation than the non-overlapped materials.
All of the above disclosed markers require defining identifying indicia by concentrating an X-ray attenuating material in the shape of the desired pattern. The concentrated attenuating material is then encapsulated or otherwise fixed to provide a marker. Concentrating the X-ray attenuating material in a desired pattern complicates the marker fabrication process increasing costs.
Furthermore, X-ray markers must often be used on both a horizontal and a non-horizontal support platform. When a platform is horizontal, the marker can be placed on the platform without it falling off. However, when the platform is angled or vertical, some means is required to hold the marker in place.
Typically, adhesives are used to stick the marker to a surface. After continued use, however, the adhesives becomes fouled and fail to stick. The marker must then be discarded or the adhesive renewed. Other methods, known in the art, include affixing a suction cup or clip to the marker, which further increase the cost of the marker.